Balboa is the ex-girlfriend of Samuel's father, Dalton Olson.
Inside a courtroom, a judge found probable cause to charge Balboa with the capital murder charge.
Andrea Beall, the prosecutor who appeared on behalf of the Harris County District Attorney's Office, said the next step is for the case to go to a grand jury, which can take up to 90 days. The grand jury will be tasked to make a determination on probable cause.
Beall added District Attorney Kim Ogg will also make determination on whether to pursue the death penalty.
According to Beall, they determined the capital murder charge for Balboa based on forensic evidence and cell phone records, as well as reviewing the evidence against statements made by Ben Rivera, Balboa's roommate who is also charged with tampering with evidence in the case.
"I'm confident we can meet our burden and get justice for Samuel," Beall said outside the courtroom.
For her part, Balboa requested for a court-appointed public defender.
This was Balboa's first appearance since her charge was upgraded last week. Like Rivera, she had already been charged with tampering with evidence.
Samuel's mother still believes boy's father is at fault
In the wake of the upgraded charge, Samuel's mother, Sarah Olson, told the media last Friday that she still has a lot of questions about how this happened.
READ MORE: Mom of boy found dead in motel room speaks after suspect charged with capital murder
Sarah specifically called out her ex-husband Dalton, claiming he still needs to answer questions.
"He was supposed to keep our son safe, and he didn't. He took him away from me. For what? To have him murdered?" Sarah said. "Honestly, the person that I feel really needs to be charged is still walking around and that's really what I'm waiting for."
Police have given no indication that Dalton is involved in the killing.
In total, three people have been charged in the case -- Balboa, Rivera, and a friend who police say drove her to Jasper to hide Sam's body.
SEE ALSO: Samuel Olson death: 3rd person charged with tampering in connection with death of 5-year-old
The medical examiner determined that Samuel died from homicidal violence with blunt trauma to the head.
Charging documents for Balboa allege that she struck him but do not say with what. On June 24, the lead prosecutor told ABC13 that they found the weapon that may have been used to kill the child.
RELATED: Samuel Olson death: Weapon that killed 5-year-old may have been found, prosecutor says
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